Who knows about oven heating elements?

[skotl]

Does anyone know about oven heating elements? I've bought two, and both have perished after the first use.

The background is that I'm making a rod heating oven (purely for giggles, not for any burning reason) and thought that something like this would be perfect (click for link):




It's rod length and shape, so I made a steel box that wraps around it, with an upper section where the rods would fit.
I wired in a 100C thermal switch which is in the rod compartment, however my heat gun suggests the element gets up to around 180C, well within its operating range.

Thing is, it worked perfectly first time (on the bench) but then failed. So I bought another (different make, but same pattern part), fitted that yesterday and the same thing has happened - worked fine on the bench the first time, and has now failed.

Both elements had continuity when I bought them and both have gone open circuit.

So I'm wondering whether I'm missing something about oven elements:

• Are they extremely fragile? Is it the motion and being knocked that's knackering them?
• Are oven heating circuits more complex than I assumed? Is there more to them than just plugging 230V up 'em?

Appreciate any thoughts

 

[Paul.]

I would have thought that they are designed to work submerged in water, using it in air is a bit like a kettle with no water in it,

 

[roofman]

£6.49 might be a reason they are breaking... the last 2 i bought were £60 each

 

[skotl]

I would have thought that they are designed to work submerged in water, using it in air is a bit like a kettle with no water in it,

It's an oven element, though, not a kettle one

£6.49 might be a reason they are breaking... the last 2 i bought were £60 each

Aye - that could be it, of course - I'd have thought they would work for a bit longer than ten minutes though

 

[WorkshopChris]

As Paul said the washing machine element will be designed to be submerged.
You would either need a oven element or dishwasher drying element.
From experience 3 phase immersion heater elements dont last very long when run dry.

 

[skotl]

I would have thought that they are designed to work submerged in water, using it in air is a bit like a kettle with no water in it,

It's an oven element, though, not a kettle one

Ahhh.... wait... it's not a flipping oven element is it?

Would washing machines immerse their elements in water?

 

[skotl]

As Paul said the washing machine element will be designed to be submerged.
You would either need a oven element or dishwasher drying element.
From experience 3 phase immersion heater elements dont last very long when run dry.

Darn. I'm even writing that it's an oven element, despite the fact it says washing machine element! Yep - that could be it.

That's a total pain - I built the rod oven (which is a work of art!) around this element

 

[roofman]

Ahhh.... wait... it's not a flipping oven element is it?

Would washing machines immerse their elements in water?

yep

 

[daleyd]

That link shows up as a washing machine element, so as Paul says probably designed for use in water

You can get small flat rubberised plate elements - maybe worth a bash, I’ll see if I can find a link

 

[skotl]

Me ==>

 

[roofman]

Me ==>

dont beat yourself up, i have on average 5 of these moments a day

 

[skotl]

That explains the rubber fitting - made it very easy to get a snug fit, presumably cos it's there to stop the water escaping

Looks like towel rail elements might be a solution...

 

[graffian]

That's a total pain - I built the rod oven (which is a work of art!) around this element

Build a water jacket into it;-)

 

[skotl]

Build a water jacket into it;-)

I considered that for around 3 seconds and then realised that introducing water to my home made bag-of-electricity probably wasn't a good idea

 

[Barlidge]

Would attaching a heat gun to your box work, kind of making it like a fan oven?

 

[brightspark]

I bet the colour changed and it went soft

 

[skotl]

Would attaching a heat gun to your box work, kind of making it like a fan oven?

This looks like it will do the job:

£9 delivered via a slow boat from China. Also looking at tumble dryer elements, but I can't find dimensions for them so the element bit might be too big.

 

[Wozzaaah]

Would you like this thread deleted?

 

[skotl]

Would you like this thread deleted?

Hah feel free, if you think it's cluttering up the place

It did the trick, though

 

[daleyd]

Have a look on RS - for not much more you can get a small cartridge heater or a flat silicone mat one - they are not hugely expensive. For a rod oven I would imagine you wouldn’t really want a “big” heat source - a small element providing even heat would be much more preferable. In a small space you might find your big heat source will be cycling on/off too rapidly.

I’d couple it with a cheap pid controller and ssr/thermocouple from eBay (just over a tenner for all those) and you’ll get perfect control.